People sometimes forget that the 'joke' in tmnt is that it does take itself seriously while still being about talking humanoid turtles.

Turtles was designed as a parody of both martial arts movies, Daredevil and 1980s action movies. Of course it's serious but we shouldn't ignore the concept of it since it stretches credibility. I personally love it. For me I always saw Turtles as a joke on the environment. The Turtles eat pizza, use hip language and love doing what normal humans do because of the environment they've been raised in. They are a product of the capitalist New York forming their sensibilities. I love that idea.